1. Field of the Invention
The present invention relates to a data processing apparatus capable of communicating with external information processing apparatuses, a data processing method, a data processing program for implementing the method, and an image processing apparatus.
2. Description of the Related Art
Conventionally, an information processing apparatus, such as a host computer or a personal computer, has been able to obtain printer-related attribute information from a printer, determine whether or not a job can be issued based on the attribute information, and control the issuance of the job based on results of the determination (for example, Japanese Laid-Open Patent Publication (Kokai) No. 2000-137590).
At the printer, an ID is added to each of a variety of types of attribute information, and the information processing apparatus acquires and identifies the attribute information based on these IDs.
In recent years, on the Internet, web services have attracted much attention. A web service is a technology that seamlessly joins a variety of services that are dispersed on a network. Using this technology, it is possible for a program to dynamically select appropriate services without any human intervention, and as such it is widely anticipated by many industries as a technology that is capable of automatically performing a desired processing.
The data exchanged through a web service is written in XML (Extensible Markup Language). The XML data is transmitted over the network using SOAP (Simple Object Access Protocol). According to SOAP, it is stipulated that HTTP (Hyper Text Transfer Protocol) or SMTP (Simple Mail Transfer Protocol) is used in a lower layer, and SOAP can be used on the Internet as easily as web browsing and an e-mail.
Moreover, technical specifications used by web services include WSDL (Web Service Description Language). WSDL is a web service description language that describes an interface for accessing a web service. A client information processing apparatus (hereinafter “client”) that uses a web service can confirm the actual connection method by referring to information described in WSDL. WSDL is standardized by W3C (World Wide Web Consortium), the technical specifications for which can be obtained from “http://www.w3.org/TR/wsdl”.
By applying the web service technology to printing, a variety of hitherto unavailable advantages can be obtained. For example, with a conventional printer, the client must identify which ID corresponds to which attribute information and acquire desired attribute information by specifying a plurality of IDs. By contrast, a printer equipped with a web service enables a user to flexibly customize access to the printer print service. For example, the connection method to the printer print service is described in WSDL. Therefore, by using a conversion/interpretation program following uniform standards based on WSDL, the client can also interpret a file described in WSDL and provide a GUI (graphical user interface) has only those items required by the user, which are extracted from the file.
Moreover, WSDL can also describe job information that can be specified when a print job is input, so that, for example, it is also possible to know in advance whether or not double-sided printing is possible by referring to the WSDL-described job information.
Thus, it is expected that printers, to which the web service technology having a variety of advantages is applied, will be further developed from now onwards.
In order to apply the web service technology described above to printing, the printer itself is required to generate a WSDL-described file (hereinafter referred to as “WSDL file”) and publish it on the network. However, if the WSDL file is unique to each printer, information that dynamically changes, such as status information including equipment information (installed hardware information) on the printer, cannot be reflected in the WSDL file.
Therefore, for example, in a WSDL file of a printer for which a hard disk is optional and that is shipped without a hard disk, “no hard disk” is written. Similarly, if, considering the fact that a hard disk is optional, information that is necessary to use a hard disk is written in the WSDL file, then the client will carry out operations required when the printer uses a hard disk, regardless of whether or not a hard disk is installed.
As a result, there is the drawback that the client transmits operations that cannot actually be executed, to the printer.